(Photo: some of our garden kale in early Spring 2008 - not a photo today as we got more snow yesterday!)
Many of the brassica greens are good sources of available calcium, required for building and maintaining bones and teeth, muscle contractions and nerve conduction, blood pressure control, along with blood clotting. Along with the traditionally promoted dairy foods and other foods that are fortified with additional calcium (such as some soy milk, tofu, and orange juice among others), kale and other brassica greens such as collards, turnip, mustard, and bok choy can be substantial dietary sources of calcium for your diet.
Here are some examples of the calcium content for brassica vegetables:
Collard greens, cooked, 1 cup - 357 mg
Turnip greens, cooked, 1 cup - 249 mg
Kale, cooked, 1 cup - 179 mg
Bok choy, cooked, 1 cup - 158 mg
Mustard greens, cooked, 1 cup - 152 mg
Broccoli, cooked, 1 cup - 94 mg
The recommended dietary intake of calcium for adults age 19 through 50 years is 1000 mg per day from food and/or supplements. An intake of 1200 mg of calcium is recommended for those age 51 years and older. By looking at the figures in the above chart, one can see that daily intake from a variety of brassica greens can provide significant calcium to a healthy diet.
In fact, a higher percentage of calcium is absorbed from some of these brassica vegetables (including kale) when compared to milk. An example to illustrate this is the following:
• Milk contains 300 mg calcium/cup x 32% absorbed = 96 mg calcium absorbed
• Kale contains 197 mg calcium/cup raw x 42% absorbed = 83 mg absorbed
One can easily see from this example how kale can be an important dietary source calcium source for forming and maintaining healthy bones and teeth, along with the other essential functions that calcium performs in our body. Thus I have a question. Why not "Got Kale?"
A very good resource regarding calcium requirements and food sources for people following a vegan diet is The Vegetarian Resource Group.
Enjoy eating your kale (and all the other brassica greens) while you picture those calcium molecules building or maintaining your bones and all its other vital functions in your body. I do!
Where kale is more than decoration on my plate!
Diana Dyer, MS, RD